Coherence (2014) turned out to be one of the more interesting SF/horror/mindfuck movies we've seen recently. We were even more impressed when we found out how it was made.
It starts with eight friends getting together for a dinner party. We learn a bit about them - the main drama is that one of them is bringing a flirty vixen who used to be sleeping with another of them, who is now in a relationship with Emily Foxler (who is sort of the protagonist). We also learn that this is the night that a dramatic comet will be visible.
Then the lights go out. After getting some candles going, one of the guests tries to call his brother, a physicst, who told him to call if he noticed anything weird when the comet passed. The phones don't work, and the entire neighborhood is dark - except one house a few blocks away. Two of the guests decide to venture over there to see if their phones work. The rest of the group is very much against this trip.
They come back, looking beaten and freaked. They have a small box that turns out to contain a ping-pong paddle and photos of everyone in the group with random numbers on the back - including one photo that could have only been taken that night. The adventurers don't want to talk about what they saw, but finally divulge: The other house looks just like this, with a dinner table set for eight. They got scared, grabbed the box and ran, falling down and getting a cut. At this point, the guy who owns the house remembers they have a generator and starts it up. Now their house has lights too.
They decide to write a note to the people in the other house to stick under their door. There's a knock on their door, and a note is slipped under - the exact same note that they are writing.
Through this all, they are generally frightened to open the door or interact with anyone outside their group. However, it's not like their group is all that sweet and kindly.
I don't want to spoil this for any of my readers, but I don't think there are any. So -SPOILER- They realize that the people who leave the house don't come back to the same reality as the one they left. In the new house, the box may contain a glove or a comb. The numbers on the back of the photos mat be different. This all relates to the physicist brother's theories of quantum coherence. So Foxler, who is freaking out over all the negativity, starts looking for a house where people are calm and nice. When she finds one, she kills her other self - and lives happily ever after?
So, interesting reality bender. Some of the odder details, like the ping-pong paddle pay off well. There aren't as many of these puzzles that get get solved later on as you might hope. There is also the undercurrent of panic related to the outside world. Is this social commentary on the fear of chaos in a disaster? Like the rioting and looting expected (but not always found) in a blackout or flood. Or was it just the way writer/director James Ward Byrkit assumes things are?
It was interesting to find out, after we'd watched, that Byrkit made this movie as an exercise in minimal resources. He got eight actors and filmed in his own living room with no crew - just himself and a camera. He also had a minimal script - just notes on what he needed to achieve in a scene. He would give the actors a note on what they needed to do, and let them improvise - and then didn't tell the other actors.
It was interesting to add this to World on a Wire and Ultrasound - although those were mind control movies, this is an alternate reality scenario. It's fun how much movies can do to alter reality.